Rare earth doped feconicu high-entropy alloy hydrogen evolution electrocatalyst, preparation method and application thereof

Abstract

This invention discloses a rare-earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst, its preparation method, and its applications. The general chemical formula of the electrocatalyst is (FeCoNiCu). 100‑n RE n The atomic ratio of Fe, Co, Ni, and Cu is 1:1:1:1, RE is Sc, Y, or La, 0 ≤ n ≤ 20, and n represents the atomic percentage of rare earth elements. The preparation method includes weighing Fe, Co, Ni, Cu, and rare earth metal raw materials according to the target atomic percentage, obtaining a master alloy ingot through arc melting under an inert atmosphere, wire-cutting the master alloy ingot into thin slices, and obtaining a hydrogen evolution electrocatalyst after grinding, cleaning, and cyclic voltammetry activation. By introducing rare earth elements and electrochemical activation, the electronic structure and reaction interface state of the high-entropy alloy surface can be adjusted, improving the hydrogen evolution reaction activity under alkaline conditions. Among them, Fe... 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 The sample exhibited excellent HER performance after CV activation, at 10 mA cm⁻¹. ‑2 The overpotential can be reduced to 78 mV, and the Tafel slope is 57 mV dec. ‑1 .

Description

Technical Field

[0001] This invention relates to a method for preparing an HER catalyst, and particularly to a rare earth element-doped high-entropy alloy preparation and application technology, belonging to the field of electrocatalysis technology. Background Technology

[0002] Hydrogen energy, with its high energy density and zero carbon emissions, is widely recognized as one of the most promising clean energy sources, and the development of water electrolysis for hydrogen production has become a strategic priority in the global energy transition. In the water electrolysis process, the hydrogen evolution reaction (HER) at the cathode is the key step determining the overall energy conversion efficiency; however, its kinetics are slow, typically requiring highly efficient electrocatalysts to reduce the reaction overpotential and accelerate the reaction process. Currently, platinum (Pt)-based catalysts are still considered the best performing material system for HER. However, Pt's extremely low global reserves and high cost severely restrict its large-scale application in industrial-scale hydrogen production. Therefore, developing highly active, stable, and cost-effective non-precious metal or low-precious metal HER electrocatalysts has become a core problem urgently needing breakthroughs in the field of electrocatalysis research.

[0003] Among numerous alternative catalytic materials, high-entropy alloys (HEAs) have seen rapid development in recent years, opening up entirely new directions for electrocatalysis research. HEAs typically consist of five or more principal elements in equimolar or near-equimolar ratios. Their high configurational entropy effectively suppresses the precipitation of intermetallic compounds and promotes the formation of single-phase solid solutions. The unique multi-principal element configuration endows HEAs with a series of "core effects" distinct from traditional alloys—lattice distortion effect, cocktail effect, and retarded diffusion effect—giving them significant advantages in electronic structure regulation, multi-active-site synergy, and structural thermal stability. Specifically, the high-entropy effect and electronic interactions effectively enhance the thermodynamic stability of the catalyst, while the retarded diffusion effect improves its stability under harsh conditions such as strong corrosion or high potentials. Based on these characteristics, high-entropy alloys can provide almost continuously distributed binding energies through multi-principal element design, synergistically stabilizing various intermediates in multi-step catalytic reactions and achieving simultaneous optimization of catalytic activity and stability. However, high-entropy alloy electrocatalytic systems still face significant challenges in practical applications. On the one hand, because HEA integrates multiple active sites, it often exhibits over-adsorption behavior, making it difficult for active species to desorb from the catalyst surface, thus limiting catalytic efficiency. On the other hand, the hydrogen evolution performance of existing HEA at industrial-grade current densities is still insufficient, the catalytic mechanism is not yet fully understood, and its application in practical electrolyzer devices is extremely limited. Addressing this key bottleneck of over-adsorption, adjusting the adsorption intensity of HEA active sites has become a crucial breakthrough for improving catalytic activity.

[0004] Against this backdrop, the introduction of rare-earth (RE) elements provides a unique regulatory pathway for the rational improvement of the electrocatalytic performance of high-entropy alloys. Rare-earth elements possess unique 4f orbital electronic configurations, low electronegativity, and significant oxygen affinity, allowing them to act as strong electron donors in alloy systems to regulate charge distribution. Studies have shown that introducing rare-earth elements into high-entropy alloys can delocalize 4f electrons through interactions between multi-metal active sites and rare-earth elements, thereby optimizing the adsorption strength of active intermediates on the HEA surface. Simultaneously, the larger atomic radii of rare-earth elements induce local lattice distortion in the HEA lattice and form surface dipole moments between rare-earth elements and active sites, further enhancing electron exchange efficiency and optimizing the reaction pathway at the catalytic interface. Furthermore, the unique 4f orbital electrons of rare-earth elements can strongly modulate the active sites through 4f-5d orbital hybridization, thereby optimizing the adsorption and desorption behavior of reaction intermediates. However, the regulation of high-entropy alloy performance by rare-earth elements exhibits significant system- and content-dependent characteristics; not all high-entropy alloys show performance improvements after the introduction of rare-earth elements. The phase structure and catalytic behavior of high-entropy alloys are influenced by factors such as element matching relationship, atomic size difference, mixing enthalpy, electronegativity difference and rare earth content. If the compatibility between rare earth elements and matrix elements is insufficient or the doping amount is too high, it may cause element segregation, second phase precipitation, excessive lattice distortion or loose structure, thereby weakening structural stability and electrocatalytic activity.

[0005] In recent years, there have been some patent reports on high-entropy alloy electrocatalytic materials. For example, patent CN101214443A discloses a high-entropy alloy catalyst containing rare earth elements and its preparation method, which prepares a multi-element alloy catalytic material containing rare earth elements through magnetic field-assisted electrodeposition. However, this system mainly uses a multi-element system such as Pd, Mn, Fe, Co, Ni, and Zn, and the preparation process is relatively complex. Moreover, it has not conducted systematic research on the alkaline hydrogen evolution reaction (HER). In addition, some existing high-entropy alloy HER materials mainly use noble metal doping, nano-support, or porous structure construction to improve catalytic performance, which has problems such as high preparation cost, complex process, and insufficient structural stability. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst to solve the problems of high price, low reserves, poor stability and complex preparation process of existing electrocatalytic hydrogen evolution (HER) catalysts.

[0007] Technical solution: The present invention provides a rare-earth-doped high-entropy alloy, wherein the chemical formula of the high-entropy alloy is (FeCoNiCu). 100-n RE nThe molar ratio of Fe, Co, Ni and Cu is 1:1:1:1.

[0008] Preferably, RE is Sc, Y, Er, or La.

[0009] More preferably, the doping content of the rare earth element satisfies 0 < n ≤ 20; preferably, n = 5, 10, 15, or 20; more preferably, n = 10. When n = 10, the resulting high-entropy alloy sheet possesses both a relatively complete and stable structure and excellent electrocatalytic performance, exhibiting the best overall performance. After CV activation and reconstruction, its hydrogen evolution performance is further improved while maintaining the structural integrity of the alloy sheet. In contrast, when n ≥ 15, due to the excessively high rare earth doping content, the alloy sheet structure gradually becomes porous, and its stability decreases significantly; during subsequent CV activation, the sheet is prone to decomposition or detachment, making it difficult to continue conducting stable electrochemical performance tests.

[0010] In the above technical solution, a series of high-entropy alloys (FeCoNiCu) were prepared by controlling different rare earth elements and their doping ratios. 100-n RE n (0 ≤ n ≤ 20) Samples. Samples with different rare earth contents exhibit different structural and performance differences. Structurally, samples with lower rare earth contents show a single-phase structure, while those with higher rare earth contents exhibit a multiphase structure. In electrocatalysis, doping with La can improve the catalyst's catalytic activity, and after CV activation, the performance undergoes a dramatic change, becoming even more superior. Among these, Fe after CV... 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 It has the best performance.

[0011] Furthermore, the overpotential of the optimal rare-earth-doped high-entropy alloy is 40 mV, and the Tafel slope is 36 mVdec⁻¹.

[0012] On the other hand, the present invention provides a method for preparing the above-mentioned rare earth-doped high-entropy alloy, comprising the following steps:

[0013] (1) Weigh the Fe, Co, Ni, Cu and rare earth metal RE raw materials according to the atomic percentage shown in (FeCoNiCu)100-nREn;

[0014] (2) The raw materials obtained in step (1) are subjected to electric arc melting under an inert atmosphere and cooled to obtain a master alloy ingot;

[0015] (3) The master alloy ingot obtained in step (2) is wire-cut into alloy sheets;

[0016] (4) The alloy sheet obtained in step (3) is decontaminated, polished and cleaned to obtain the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst.

[0017] Furthermore, the preparation method further includes: (5) placing the alloy sheet treated in step (4) in an alkaline electrolyte for cyclic voltammetric activation to obtain the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst.

[0018] Furthermore, in step (1), the purity of Fe, Co, Ni, Cu and RE raw materials is not less than 99 wt.%.

[0019] Further, in step (2), the raw material is placed in a high vacuum electric arc melting furnace, first evacuated to a vacuum level not higher than 1×10-3 Pa, then argon gas is introduced as a protective atmosphere, and the melting is repeated at least 5 times and cooled for no less than 60 min.

[0020] Furthermore, in step (4), the alloy sheet is successively polished by SiC sandpaper of different mesh sizes and then ultrasonically cleaned in anhydrous ethanol.

[0021] Further, in step (5), the alkaline electrolyte is KOH solution, the scanning rate of cyclic voltammetry activation is 10 mV s-1, and the number of cycles is 500-2000.

[0022] This invention provides an application of the above-mentioned rare earth-doped high-entropy alloy in the preparation of electrocatalytic oxygen evolution catalysts.

[0023] Compared with existing technologies, this invention introduces rare earth elements Sc, Y, or La into the FeCoNiCu high-entropy alloy system for the first time. Through the unique 4f orbital electronic regulation effect of rare earth elements and the surface reconstruction effect induced by CV electrochemical activation, the synergistic optimization of the electronic structure and active sites on the surface of the high-entropy alloy is achieved. Specifically, the La-doped sample exhibits significantly enhanced hydrogen evolution activity after CV activation, while the Fe... 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 In 1 M KOH electrolyte, 10 mAcm -2 The hydrogen evolution overpotential at current density can be reduced to 78 mV, and the Tafel slope to as low as 57 mV dec. -1The results show that the performance is significantly better than that of undoped high-entropy alloy comparative samples and most existing non-precious metal high-entropy alloy HER catalytic systems. Furthermore, the improvement in hydrogen evolution performance of FeCoNiCu high-entropy alloys by rare earth elements in this invention is not a result that can be expected simply by doping, but rather a performance regulation achieved through the synergistic effect of a specific alloy matrix, rare earth element type, doping content, and cyclic voltammetric activation. Simultaneously, this invention uses arc melting combined with wire cutting to obtain bulk alloy sheets that can be directly used as working electrodes, avoiding complex carrier loading and binder treatment processes, and has advantages such as simple process, structural stability, and ease of large-scale preparation. Further, this invention found that when the rare earth doping content is n=10, the alloy sheet exhibits both excellent structural stability and electrocatalytic performance; as the rare earth content continues to increase, the sheet structure gradually becomes looser and is prone to decomposition during CV activation, indicating that appropriate rare earth doping plays an important role in maintaining the structural stability of the high-entropy alloy and synergistically optimizing its catalytic performance.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0025] (1) This invention uses Fe, Co, Ni, and Cu as matrix elements and introduces rare earth elements such as Sc, Y, or La to construct a rare earth-doped FeCoNiCu high-entropy alloy system, which can improve the hydrogen evolution reaction interface through the synergistic effect of multiple elements and the regulation effect of rare earth elements.

[0026] (2) The preparation method described in this invention uses steps such as arc melting, wire cutting, surface grinding and cleaning and electrochemical activation. The process route is relatively simple and it is easy to obtain alloy sheets with uniform composition that can be directly used as working electrodes.

[0027] (3) In this invention, the La-doped sample exhibits a significant performance improvement after cyclic voltammetry activation, while Fe... 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 In 1 M KOH, 10 mA cm -2 The hydrogen evolution overpotential at the current density is 78 mV, and the Tafel slope is 57 mV dec. -1 Significantly superior to undoped Fe 25 Co 25 Ni 25 Cu 25 Comparison samples.

[0028] (4) This invention provides a new technical solution for the composition design and surface structure control of high-entropy alloy hydrogen evolution electrocatalysts by combining rare earth element selection and electrochemical activation. Attached Figure Description

[0029] Figure 1 (FeCoNiCu) 100-n La n (n=5, 10, 15, 20) Linear voltammetric curves of samples before CV activation.

[0030] Figure 2 The (FeCoNiCu) samples from Examples 1-6 and Comparative Examples 1-2 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) X-ray diffraction pattern of the sample;

[0031] Figure 3 The (FeCoNiCu) samples from Examples 1-3 and Comparative Example 1 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) Linear voltammetric curves of the sample before CV activation.

[0032] Figure 4 The (FeCoNiCu) samples from Examples 4-6 and Comparative Example 2 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) Linear voltammetric curves of the sample after CV activation.

[0033] Figure 5 The (FeCoNiCu) samples from Examples 1-3 and Comparative Example 1 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) Tafel slope of the sample before CV activation.

[0034] Figure 6 The (FeCoNiCu) samples from Examples 4-6 and Comparative Example 2 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) Tafel slope of sample after CV activation.

[0035] Figure 7 The (FeCoNiCu) samples from Examples 1-6 and Comparative Examples 1-2 are examples of this. 100-n RE n (RE=Y, Sc, La, n=10) Comparison of hydrogen evolution overpotentials before and after CV activation of the sample. Detailed Implementation

[0036] The present application will now be described in detail with reference to specific embodiments.

[0037] Example 1:

[0038] A Fe 22.5 Co 22.5 Ni 22.5 Cu22.5 Y 10 The preparation method and application of rare earth doping include the following steps:

[0039] (1) According to the molecular formula Fe 22.5 Co 22.5 Ni 22.5 Cu 22.5 Y 10 The following components were weighed and batched according to their atomic percentages: iron block 4.033g, cobalt block 4.268g, nickel block 4.241g, copper block 4.599g, and yttrium block 2.896g. All elements had a purity greater than 99%. The weighed materials were then ultrasonically cleaned in anhydrous ethanol to remove any remaining impurities, and subsequently dried.

[0040] (2) Place the master element alloy prepared in step (1) into a high-vacuum electric arc melting furnace in order of melting point from bottom to top, consisting of copper, nickel, cobalt, yttrium, and iron. First, evacuate the furnace to a high vacuum of not less than 1×10⁻⁶. -3 Pa, then fill the cavity with an appropriate amount of argon gas as a protective gas; use electric arc melting, melt repeatedly for at least 5 times, cool for 60 minutes, take out the sample, wipe with alcohol, weigh the master alloy, the error should not exceed 0.02 g, finally put it into a bag and clean the electric arc furnace.

[0041] (3) The master alloy ingot obtained in step (2) is wire cut into thin slices with dimensions of 0.6mm*10mm*5mm.

[0042] (4) The thin sheet obtained in step (3) is ultrasonically cleaned in anhydrous ethanol to remove oil stains. The high entropy alloy sheet is then polished with SiC sandpaper of different grits (600 grit, 800 grit, 1000 grit and 2000 grit) to remove the surface oxide layer and make the surface relatively smooth. Then, the surface impurities are ultrasonically cleaned with anhydrous ethanol. Finally, the cleaned thin sheet is vacuum-sealed for storage.

[0043] (5) Electrochemical HER performance test: The test adopted a standard three-electrode test, with a mercuric oxide electrode as the reference electrode, a graphite rod electrode as the counter electrode, and the processed sample sheet as the working electrode. The geometric area of ​​the sample sheet participating in the reaction was (0.5 × 0.5 cm²). 2 Electrochemical HER performance was tested in 1M KOH electrolyte solution, and all data were obtained through iR compensation testing. The overpotential of the HER at 10 mA was 245 mV, and the overpotential at 100 mA was 364 mV, with a Tafel slope of 131 mV·dec. -1 .

[0044] Example 2:

[0045] Compared to Example 1, the sample composition ratio has changed in this example, and the chemical formula is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 Sc 10 The different steps are as follows: the iron block weighs 4.346g, the cobalt block weighs 4.586g, the nickel block weighs 4.568g, the copper block weighs 4.945g, and the scandium block weighs 1.555g. Everything else is the same as in Example 1. Its HER10mA overpotential is 299 mV, and the Tafel slope is 134 mV·dec. -1 .

[0046] Example 3:

[0047] Compared to Example 1, the sample composition ratio has changed in this example, and the chemical formula is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 The different steps are as follows: the iron block weighs 3.739g, the cobalt block weighs 3.945g, the nickel block weighs 3.929g, the copper block weighs 4.254g, and the scandium block weighs 4.133g. Everything else is the same as in Example 1. Its overpotential at HER10mA is 230mV, its overpotential at 100mA is 331mV, and its Tafel slope is 118mV·dec. -1 .

[0048] Example 4:

[0049] In this embodiment, the sample component is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 Y 10 This includes the following steps:

[0050] (1) According to the molecular formula Fe 22.5 Co 22.5 Ni 22.5 Cu 22.5 Y 10 The following components were weighed and batched according to their atomic percentages: iron block 4.033g, cobalt block 4.268g, nickel block 4.241g, copper block 4.599g, and yttrium block 2.896g. All elements had a purity greater than 99%. The weighed materials were then ultrasonically cleaned in anhydrous ethanol to remove any remaining impurities, and subsequently dried.

[0051] (2) Place the master element alloy prepared in step (1) into a high-vacuum electric arc melting furnace in order of melting point from bottom to top, consisting of copper, nickel, cobalt, yttrium, and iron. First, evacuate the furnace to a high vacuum of not less than 1×10⁻⁶. -3 Pa, then fill the cavity with an appropriate amount of argon gas as a protective gas; use electric arc melting, melt repeatedly for at least 5 times, cool for 60 minutes, take out the sample, wipe with alcohol, weigh the master alloy, the error should not exceed 0.02 g, finally put it into a bag and clean the electric arc furnace.

[0052] (3) The master alloy ingot obtained in step (2) is wire cut into thin slices with dimensions of 0.6mm*10mm*5mm.

[0053] (4) The thin sheet obtained in step (3) is ultrasonically cleaned in anhydrous ethanol to remove oil stains. The high entropy alloy sheet is then polished with SiC sandpaper of different grits (600, 800, 1000, 2000) to remove the surface oxide layer and make the surface relatively smooth. Then, the surface impurities are ultrasonically cleaned with anhydrous ethanol. Finally, the cleaned thin sheet is vacuum-sealed for storage.

[0054] (5) Perform CV activation on the thin film obtained in step (4). First, divide the thin film of the above size into a working area (0.5 × 0.5 cm). 2 The working region was then immersed in a 1KOH solution, and CV cycle activation was performed within the LSV potential range at a scan rate of 10 mV / s and a scan count of 500-2000 cycles. Thin films with different surface structures and properties were obtained.

[0055] (6) Electrochemical HER performance test: The test adopted a standard three-electrode test, with a mercuric oxide electrode as the reference electrode, a graphite rod electrode as the counter electrode, and the processed sample sheet as the working electrode. The geometric area of ​​the sample sheet participating in the reaction was (0.5 × 0.5 cm²). 2 Electrochemical HER performance was tested in 1M KOH electrolyte solution, and all data were obtained through iR compensation testing. The overpotential of the HER at 10 mA was 221 mV, and the overpotential at 100 mA was 350 mV, with a Tafel slope of 124 mV·dec. -1 .

[0056] Example 5:

[0057] Compared to Example 4, the sample composition ratio has changed in this example, and the chemical formula is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 Sc 10The different steps are as follows: the iron block weighs 4.346g, the cobalt block weighs 4.586g, the nickel block weighs 4.568g, the copper block weighs 4.945g, and the scandium block weighs 1.555g. Everything else is the same as in Example 1. Its HER10mA overpotential is 282mV, and the Tafel slope is 155mV·dec. -1 .

[0058] Example 6:

[0059] Compared to Example 4, the sample composition ratio has changed in this example, and the chemical formula is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 The different steps are as follows: the iron block weighs 3.739g, the cobalt block weighs 3.945g, the nickel block weighs 3.929g, the copper block weighs 4.254g, and the scandium block weighs 4.133g. Everything else is the same as in Example 1. Its overpotential at HER10mA is 78mV, at 100mA it is 207mV, and at 1000mA it is 341mV, with a Tafel slope of 57mV·dec. -1 .

[0060] Comparative Example 1:

[0061] Comparative Example 1 below serves as a comparison example with Examples 1-3 above, for further comparison of the HER catalytic performance of water electrolysis. Compared to Examples 1-3, the sample in the comparative example is not doped with rare earth elements and has the chemical formula Fe. 25 Co 25 Ni 25 Cu 25 The preparation method and electrochemical HER performance testing were the same as in Example 1. Its HER 10mA overpotential was 315mV, and the Tafel slope was 142mV·dec. -1 .

[0062] Comparative Example 2:

[0063] Comparative Example 2 below serves as a comparison example with Examples 4-6 above, and is used to further compare the HER catalytic performance of water electrolysis after CV activation. Compared to Examples 4-6, the sample in the comparative example is not doped with rare earth elements, and its chemical formula is Fe. 25 Co 25 Ni 25 Cu 25 The preparation method and electrochemical HER performance testing were the same as in Example 4. Its HER 10mA overpotential was 311mV, and the Tafel slope was 135mV·dec. -1 .

[0064] Performance Results Summary

[0065] The electrochemical hydrogen evolution performance results of the above examples and comparative examples are summarized below. Among them, Fe... 25 Co 25 Ni 25 Cu 25 Y 10 Fe 25 Co 25 Ni 25 Cu 25 Sc 10 and Fe 25 Co 25 Ni 25 Cu 25 La 10 These correspond to the Y, Sc, and La doped samples with n=10 in the above embodiments, respectively.

[0066] serial number RE / sample CV activation η10 / mV η100 / mV η1000 / mV <![CDATA[Tafel / (mV dec -1 )]]> Comparative Example 1 none no 315 - - 142 Example 1 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Y 10 ]]> no 245 364 - 131 Example 2 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Sc 10 ]]> no 299 - - 134 Example 3 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Day 10 ]]> no 230 331 - 118 Comparative Example 2 none yes 311 - - 135 Example 4 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Y 10 ]]> yes 221 350 - 124 Example 5 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Sc 10 ]]> yes 282 - - 155 Example 6 <![CDATA[Fe 25 Co 25 Ni 25 Cu 25 Day 10 ]]> yes 78 207 341 57

[0067] As can be seen from the above examples and comparative examples, the introduction of rare earth elements can alter the HER catalytic performance of FeCoNiCu high-entropy alloys, with the La-doped sample showing the most significant performance improvement after CV activation. Compared to the undoped sample, the La10 sample, after CV activation, exhibited a higher performance at 10 mA cm⁻¹. -2 The hydrogen evolution overpotential was significantly reduced and the Tafel slope was also significantly decreased, indicating that La doping and electrochemical activation synergistically improved the hydrogen evolution reaction kinetics.

Claims

1. A rare-earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst, characterized in that, The electrocatalyst comprises Fe, Co, Ni, Cu, and rare earth element RE, with the general chemical formula (FeCoNiCu). 100-n RE n The atomic ratio of Fe, Co, Ni and Cu is 1:1:1:1, RE is Sc, Y or La, 0≤n≤20, and n represents the atomic percentage of RE.

2. The rare-earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst according to claim 1, characterized in that, n = 5, 10, 15 or 20.

3. The rare-earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst according to claim 1 or 2, characterized in that, The RE is La, and the electrocatalyst is Fe. 22.5 Co 22.5 Ni 22.5 Cu 22.5 La 10 .

4. The rare-earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst according to claim 1, characterized in that, The electrocatalyst is an alloy sheet obtained by wire cutting a master alloy ingot. The alloy sheet is then subjected to surface polishing, ultrasonic cleaning with anhydrous ethanol, and cyclic voltammetric activation treatment to obtain the electrocatalyst.

5. A method for preparing the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) According to (FeCoNiCu) 100-n RE n Weigh the Fe, Co, Ni, Cu and rare earth metal RE raw materials as shown in the atomic percentages; (2) The raw materials obtained in step (1) are subjected to electric arc melting under an inert atmosphere and cooled to obtain a master alloy ingot; (3) The master alloy ingot obtained in step (2) is wire-cut into alloy sheets; (4) The alloy sheet obtained in step (3) is subjected to decontamination, polishing and cleaning treatment to obtain the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst.

6. The preparation method according to claim 5, characterized in that, Also includes: (5) The alloy sheet processed in step (4) is placed in an alkaline electrolyte for cyclic voltammetric activation to obtain the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst.

7. The preparation method according to claim 5, characterized in that, In step (2), the raw materials are placed in a high-vacuum electric arc melting furnace, and the vacuum is first evacuated to a level not exceeding 1×10⁻⁶. -3 Pa, then purge with argon as a protective atmosphere, and repeat the melting process at least 5 times and cool for at least 60 minutes.

8. The preparation method according to claim 5, characterized in that, In step (4), the alloy sheet is successively polished by SiC sandpaper of different mesh sizes and then ultrasonically cleaned in anhydrous ethanol.

9. The preparation method according to claim 6, characterized in that, In step (5), the alkaline electrolyte is KOH solution, and the scan rate for cyclic voltammetry activation is 10 mV s. -1 The number of cycles is 500-2000.

10. The application of the rare earth-doped FeCoNiCu high-entropy alloy hydrogen evolution electrocatalyst according to any one of claims 1 to 5 in the preparation of alkaline water electrolysis hydrogen evolution reaction electrode or hydrogen evolution reaction catalyst.

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